参数资料
| 型号： | LT1175CT-5#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/20页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO -5V .5A TO220 |
| 标准包装： | 50 |
| 稳压器拓扑结构： | 负，固定式 |
| 输出电压： | -5V |
| 输入电压： | 可下调至 -20V |
| 电压 - 压降（标准）： | 0.5V @ 500mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 500mA |
| 电流 - 限制（最小）： | 可调式 |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 通孔 |
| 封装/外壳： | TO-220-5 成形引线 |
| 供应商设备封装： | TO-220-5 |
| 包装： | 管件 |
| 产品目录页面： | 1326 (CN2011-ZH PDF) |
LT1175
APPLICATIONS INFORMATION
Note to Reader: To avoid confusion when working with
negative voltages (is –6V more or less than –5V?), I have
decided to treat the LT1175 as if it were a positive regulator
and express all voltages as positive values, both in text and
in formulas. If you do the same and simply add a negative
The LT1175-5 is a ?xed 5V design with the SENSE pin
acting as a Kelvin connection to the output. Normally the
SENSE pin and the OUTPUT pin are connected directly
together, either close to the regulator or at the remote
load point.
sign to the eventual answer, confusion should be avoided.
Please don’t give me a hard time about “preciseness” or
SHUTDOWN
LOGIC
> 2V OR < –2V TO
TURN REGULATOR ON
“correctness.” I have to ?eld phone calls from around
the world and this is my way of dealing with a multitude
of conventions. Thanks for your patience.
+
C IN
+
SHDN
GND
R1
383k
1%
Setting Output Voltage
The LT1175 adjustable version has a feedback sense
V IN
I LIM2
I LIM4
SENSE
LT1175
OUTPUT
R2
825k
1%
C OUT
≥ 0.1μF
V OUT
–12V
voltage of 3.8V with a bias current of approximately 75nA
?owing out of the SENSE pin. To avoid output voltage
errors caused by this current, the output divider string
(see Figure 1) should draw about 25μA. Table 1 shows
suggested resistor values for a range of output voltages.
The second part of the table shows resistor values which
draw only 10μA of current. Output voltage error caused
by bias current with the lower valued resistors is about
0.4% maximum and with the higher values, about 1%
maximum. A formula is also shown for calculating the
resistors for any output voltage.
Table 1. Suggested Divider Resistors
1175 F01
Figure 1. Typical LT1175 Adjustable Connection
Setting Current Limit
The LT1175 uses two I LIM pins to set current limit (typical)
at 200mA, 400mA, 600mA or 800mA. The corresponding
minimum guaranteed currents are 130mA, 260mA, 390mA
and 520mA. This allows the user to select a current limit
tailored to his speci?c application and prevents the situa-
tion where short-circuit current is many times higher than
full-load current. Problems with input supply overload or
excessive power dissipation in a faulted load are prevented.
OUTPUT
VOLTAGE
5V
6V
8V
10V
12V
15V
R1
I DIV = 25μA
150k
150k
150k
150k
150k
150k
R2
NEAREST 1%
47.5k
86.6k
165k
243k
324k
442k
R1
I DIV = 10μA
383k
383k
383k
383k
383k
383k
R2
NEAREST 1%
121k
221k
422k
619k
825k
1.13M
Power limiting in the form of foldback current limit is built
in and reduces current limit as a function of input-to-output
voltage differential for differentials exceeding 14V. See the
graph in Typical Performance Characteristics. The LT1175
is guaranteed to be blowout-proof regardless of current
limit setting. The power limiting combined with thermal
shutdown protects the device from destructive junction
temperatures under all load conditions.
R 1 =
(
)( )
R 1 ( V
? 3 . 8 V ) ? Taking SENSE pin bias ?
R2 =
3 . 8 V + R 1 ( )
3.8 V
I DIV
R 1 V OUT ? 3 . 8 V
R 2 = Simple formula
3 . 8 V
OUT
? ?
I FB ? current into account ?
I DIV = Desired divider current
Shutdown
In shutdown, the LT1175 draws only about 10μA. Special
circuitry is used to minimize increases in shutdown cur-
rent at high temperatures, but a slight increase is seen
above 125°C. One option not taken was to actively pull
down on the output during shutdown. This means that the
output will fall slowly after shutdown is initiated, at a rate
determined by load current plus the 12μA internal load,
and the size of the output capacitor. Active pull-down is
1175ff
9
相关PDF资料 |
PDF描述 |
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| LT1175CT#PBF | IC REG LDO NEG ADJ .5A TO220 |
| SK3R3M250ST | CAP ALUM 3.3UF 250V 20% RADIAL |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1175CT-5-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Negative Low Dropout Micropower Regulator |
| LT1175CT-5-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Negative Low Dropout Micropower Regulator |
| LT1175CT-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Negative Low Dropout Micropower Regulator |
| LT1175CT-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Negative Low Dropout Micropower Regulator |
| LT1175CT-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Negative Low Dropout Micropower Regulator |
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